UPSC Prelims 1995 · General Studies
Question 148: Basic Numeracy
Out of a total of 120 musicians in a club, 5 % can play all the three instruments—guitar, violin and flute. It so happens that the number of musicians who can play any two and only two of the above instruments is 30. The number of musicians who can play the guitar alone is 40. What is the total number of those who can play violin alone or flute alone?
AnswerThe answer is (b).
Musicians who play all three: 5% of 120 = 6. Exactly two instruments: 30. Guitar alone: 40. Assuming each musician plays at least one instrument, the rest play violin alone or flute alone: 120 - 6 - 30 - 40 = 44. Remember: when every person is in exactly one group, subtract the known groups from the total.
Why each option is right or wrong
- (a) 45 is one too many: 6 + 30 + 40 + 44 = 120.
- (b) Right: 44.
- (c) 38 leaves 6 musicians unaccounted for.
- (d) 30 leaves 14 musicians unaccounted for.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1995, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.